"Gear Ratio" of the Labview Robotics Starter Kit?

[Xandro]

Hi! Im working on the odometry for my Starter Kit (the 4 wheel model) based on the book "Where I Am?" - You can download the book for free here: http://www-personal.umich.edu/~johannb/position.htm In page 20 the theory states that the factor which translates the number of pulses to linear distance is: Cm = PI*D/(n*Ce) D: Wheel Diameter (mm) = 4`` = 0.1016mm n = Gear Ratio= ¿? Ce = Encoder Resolution (PPR) = 400 PPR So, linear distance = Cm * N_pulses Im not sure how I could calculate the Gear Ratio of the LR Starter Kit, taking into acount that there are 4 gears interconected to each pair of wheels. I found in a paper of the UNCC that the gear ratio of the Starter Kit is 83:1, but if I try n=83 the distances don´t make any sense! - UNCC Course Lab 2 (Assignement PDF, page 1): """Gear Ratio: This is the amount of revolutions it takes the motor to complete for every 1 revolution of the wheel. The gear ratio of the daNI Robotic platform is approximately 83:1. (This value is taking the motor gear ratio into account)""" If someone has the Gear Ratio calculated beforehand, or can give me some indications of how to calculate it (or tell me if Im doing anything worng with the units!), could you help me, please?

[CMal · Accepted solution]

Xandro,

I'm not sure where the value of 83:1 came from, but I can tell you that the Starter Kit 1.0 wheels have a gear ratio of exactly 2 motor turns per wheel turn.  The motor is mounted to a 40-tooth gear, which meshes with the 80-tooth gears that are mounted to the wheels.  This means the gear ratio is 2:1.  Note that the Starter Kit 2.0 has a gear ratio of 1:1.

Chris M

[Xandro]

Thank you very much for the explanation, and the odometry works now with the n=2 gear ratio! By the way, I dont know why my posts dont show paragraphs, I wrote them. Sorry for the inconvenience. This is where i found the 83:1 gear ratio: http://webpages.uncc.edu/~jmconrad/ECGR4161-2011-05/labs/UNCC_Lab%202%20-%20Motor%20Control.pdf